MAINTENANCE MATTERS
Inspecting your shock absorbers

Keeping your suspension system in top working order doesn't have to be a bumpy ride. Key are your coach's shock absorbers, which absorb energy and dampen the suspension movement. The front and trailing axles have two shock absorbers each, and the drive axle has four shock absorbers. Shocks are mounted in rubber eye bushings at the upper end and bayonet style rubber biscuits at the lower end.

A little prevention can go a long way. Our experts recommend the following procedures for inspecting your shocks. Alway sconsult your maintenance manual and follow all safety precautions.

Inspect shock absorbers every 50,000 miles or when any suspension components are repaired or replaced. Also inspect shock absorbers if the coach has uneven tire wear, ride deterioration or excessive vibration. Shock absorbers are not adjustable and cannot be repaired. Defective shock absorbers must be replaced.

1. Inspect shock mounts.
2. Ensure that fasteners are tight.
3. Inspect shock absorber body for physical damage or evidence of leakage.
4. Inspect shock absorber rod for bending, nicks, scratches or evidence of leakage. A light film of oil on the rod is normal.
5. Inspect the rubber bushings for deterioration.
6. Road-test the coach.
7. If ride deterioration indicates that a shock has failed internally, perform a shock absorber heat test.

Misting
Misting is a normal condition for the shock. During operation, small amounts of shock fluid evaporate through the upper seal of the shock and condense on the outside of the shock body.  Road grime often coats the body of a misting shock.

Leaking
A leaking shock shows clear signs of fluid leaking in streams from the upper seal. These streams can be seen best when the shock is fully extended. Inspect as far up the main body of the shock as possible. A leaking shock must be replaced.

Broken Upper and Lower Bushings
These can be replaced very easily and are considered a regular maintenance item on a shock absorber.

Conducting a Shock Absorber Heat Test
Shock absorbers operate between ambient temperature and 350°F.  A properly operating shock will be warm or hot to the touch after normal use.

1. Drive the coach at moderate speeds for 15 minutes.
2. Elevate and block the coach.
3. Touch the chassis near a shock absorber, then carefully touch the shock absorber body below the dust cover. The shock absorber should be warmer than the chassis.
4. Repeat for all shock absorbers on that axle. All shock absorbers on one axle should be approximately the same temperature.
5. Replace any shock absorber that is cooler than the chassis, or is noticeably cooler than the other shocks on the same axle.
6. Shake the shock. Metallic rattling indicates internal failure.
7. Repeat the test for all axles.  Different temperatures from axle to axle do not indicate failure.

Inspecting for Improper Installation
Watch out for these signs:

• Washers installed backwards.
• Shock absorber upside down.

The FYI from MCI editorial staff values your feedback. Please e-mail any suggestions, comments, or ideas for future articles to fyi@mcicoach.com.